A Hot Saturn Orbiting an Oscillating Late Subgiant Discovered by TESS

Huber, Daniel; Chaplin, William J.; Chontos, Ashley; Kjeldsen, Hans; Christensen-Dalsgaard, Jørgen; Bedding, Timothy R.; Ball, Warrick; Brahm, Rafael; Espinoza, Nestor; Henning, Thomas; Jordán, Andrés; Sarkis, Paula; Knudstrup, Emil; Albrecht, Simon; Grundahl, Frank; Fredslund Andersen, Mads; Pallé, Pere L.; Crossfield, Ian; Fulton, Benjamin; Howard, Andrew W.; Isaacson, Howard T.; Weiss, Lauren M.; Handberg, Rasmus; Lund, Mikkel N.; Serenelli, Aldo M.; Rørsted Mosumgaard, Jakob; Stokholm, Amalie; Bieryla, Allyson; Buchhave, Lars A.; Latham, David W.; Quinn, Samuel N.; Gaidos, Eric; Hirano, Teruyuki; Ricker, George R.; Vanderspek, Roland K.; Seager, Sara; Jenkins, Jon M.; Winn, Joshua N.; Antia, H. M.; Appourchaux, Thierry; Basu, Sarbani; Bell, Keaton J.; Benomar, Othman; Bonanno, Alfio; Buzasi, Derek L.; Campante, Tiago L.; Çelik Orhan, Z.; Corsaro, Enrico; Cunha, Margarida S.; Davies, Guy R.; Deheuvels, Sebastien; Grunblatt, Samuel K.; Hasanzadeh, Amir; Di Mauro, Maria Pia; García, Rafael A.; Gaulme, Patrick; Girardi, Léo; Guzik, Joyce A.; Hon, Marc; Jiang, Chen; Kallinger, Thomas; Kawaler, Steven D.; Kuszlewicz, James S.; Lebreton, Yveline; Li, Tanda; Lucas, Miles; Lundkvist, Mia S.; Mann, Andrew W.; Mathis, Stéphane; Mathur, Savita; Mazumdar, Anwesh; Metcalfe, Travis S.; Miglio, Andrea; Monteiro, Mário J. P. F. G.; Mosser, Benoit; Noll, Anthony; Nsamba, Benard; Ong, Jia Mian Joel; Örtel, S.; Pereira, Filipe; Ranadive, Pritesh; Régulo, Clara; Rodrigues, Thaíse S.; Roxburgh, Ian W.; Silva Aguirre, Victor; Smalley, Barry; Schofield, Mathew; Sousa, Sérgio G.; Stassun, Keivan G.; Stello, Dennis; Tayar, Jamie; White, Timothy R.; Verma, Kuldeep; Vrard, Mathieu; Yıldız, M.; Baker, David; Bazot, Michaël; Beichmann, Charles; Bergmann, Christoph; Bugnet, Lisa et al.
Referencia bibliográfica

The Astronomical Journal, Volume 157, Issue 6, article id. 245, 14 pp. (2019).

Fecha de publicación:
6
2019
Número de autores
142
Número de autores del IAC
3
Número de citas
86
Número de citas referidas
77
Descripción
We present the discovery of HD 221416 b, the first transiting planet identified by the Transiting Exoplanet Survey Satellite (TESS) for which asteroseismology of the host star is possible. HD 221416 b (HIP 116158, TOI-197) is a bright (V = 8.2 mag), spectroscopically classified subgiant that oscillates with an average frequency of about 430 μHz and displays a clear signature of mixed modes. The oscillation amplitude confirms that the redder TESS bandpass compared to Kepler has a small effect on the oscillations, supporting the expected yield of thousands of solar-like oscillators with TESS 2 minute cadence observations. Asteroseismic modeling yields a robust determination of the host star radius (R ⋆ = 2.943 ± 0.064 R ⊙), mass (M ⋆ = 1.212 ± 0.074 M ⊙), and age (4.9 ± 1.1 Gyr), and demonstrates that it has just started ascending the red-giant branch. Combining asteroseismology with transit modeling and radial-velocity observations, we show that the planet is a “hot Saturn” (R p = 9.17 ± 0.33 R ⊕) with an orbital period of ∼14.3 days, irradiance of F = 343 ± 24 F ⊕, and moderate mass (M p = 60.5 ± 5.7 M ⊕) and density (ρ p = 0.431 ± 0.062 g cm‑3). The properties of HD 221416 b show that the host-star metallicity–planet mass correlation found in sub-Saturns (4–8 R ⊕) does not extend to larger radii, indicating that planets in the transition between sub-Saturns and Jupiters follow a relatively narrow range of densities. With a density measured to ∼15%, HD 221416 b is one of the best characterized Saturn-size planets to date, augmenting the small number of known transiting planets around evolved stars and demonstrating the power of TESS to characterize exoplanets and their host stars using asteroseismology.
Proyectos relacionados
Helio and Asteroseismologia
Sismología Solar y Estelar y Búsqueda de Exoplanetas
Los objetivos genéricos de este Proyecto son: 1) el estudio de la estructura y dinámica del interior solar, 2) la extensión de dicho estudio al caso de otras estrellas, 3) la búsqueda y caracterización de planetas extrasolares por métodos fotométricos (principalmente mediante el método de tránsitos) y espectroscópico (variaciones en la velocidad
Savita
Mathur